AD1890/AD1891

REV. 0

–5–

AD1890/AD1891 PIN LIST

Serial Input Interface

Pin Name Number

I/O

Description

DATA_I

3

I

Serial input, MSB first, containing two channels of 4- to 20-bits of twos-complement data per

channel. AD1891 ONLY: Maximum of 16 data bits per channel; additional bits ignored.

BCLK_I

4

I

Bit clock input for input data.

WCLK_I

5

I

Word clock input for input data. This input is rising edge sensitive. (Not required in LR input data

clock triggered mode [TRGLR_I = HI].)

LR_I

6

I

Left/right clock input for input data. Must run continuously.

Serial Output Interface

Pin Name Number

I/O

Description

DATA_O

23

O

Serial output, MSB first, containing two channels of 4- to 24-bits of twos-complement data per

channel.

BCLK_O

26

I

Bit clock input for output data.

WCLK_O

25

I

Word clock input for output data. This input is rising edge sensitive. (Not required in LR output

data clock triggered mode [TRGLR_O = HI].)

LR_O

24

I

Left/right clock input for output data. Must run continuously.

Input Control Signals

Pin Name Number

I/O

Description

BKPOL_I

10

I

Bit clock polarity. LO: Normal mode. Input data is sampled on rising edges of BCLK_I. HI:

Inverted mode. Input data is sampled on falling edges of BCLK_I.

TRGLR_I

11

I

Trigger on LR_I. HI: Changes in LR_I indicate beginning

WCLK_I indicates beginning of valid input data.

MSBDLY_I 12

I

MSB delay. HI: Input data is delayed one BCLK_I after either LR_I (TRGLR_I = HI) or WCLK_I

(TRGLR_I = LO) indicates the beginning of valid input data. Included for I

compatibility. LO: No delay.

NOTE

Group Delay

Intuitively, the time interval required for a full-level input pulse

to appear at the converter’s output, at full level, expressed in

milliseconds (ms). More precisely, the derivative of radian phase

with respect to radian frequency at a given frequency.

Transport Delay

The time interval between when an impulse is applied to the

converters input and when the output starts to be affected by

this impulse, expressed in milliseconds (ms). Transport delay is

independent of frequency.

DEFINITIONS

Dynamic Range

The ratio of a near full-scale input signal to the integrated noise

in the passband (0 to

≈20 kHz), expressed in decibels (dB). Dy-

namic range is measured with a –60 dB input signal and

“60 dB” arithmetically added to the result.

Total Harmonic Distortion + Noise

Total Harmonic Distortion plus Noise (THD+N) is defined as

the ratio of the square root of the sum of the squares of the val-

ues of the harmonics and noise to the rms value of a sinusoidal

input signal. It is usually expressed in percent (%) or decibels.

Interchannel Phase Deviation

Difference in input sampling times between stereo channels, ex-

pressed as a phase difference in degrees between 1 kHz inputs.